Pokemon Go Adventure Sync Function

I recently switched to the iPhone 11 Pro Max and my Pokemon Go Adventure Sync will no longer work. When I go to turn it on (settings, privacy, health) there are no apps listed under health. Some articles online I have read that the only way to make it work again is to delete the Pokemon App and then download it again. If I delete the Pokemon App will I lose my progress/level/pokemon, etc? Is there another way to make adventure sync work without deleting the app? Thank you for the help!